Today, non-aqueous electrolyte secondary batteries are in wide use as secondary batteries with high energy density, in which lithium ions for example are transferred between a positive electrode and a negative electrode to carry out charge and discharge.
In such a non-aqueous electrolyte secondary battery in general, a composite oxide of a lithium transition metal having a layered structure of lithium nickel oxide (LiNiO2), lithium cobalt oxide (LiCoO2) or the like is used as the positive electrode, and a carbon material capable of storing and releasing lithium, a lithium metal, a lithium alloy, or the like is used as the negative electrode (see, for example, Patent Document 1).
Using the above-mentioned non-aqueous electrolyte secondary battery, a discharge capacity from 150 mAh/g to 180 mAh/g, a potential of about 4 V and a theoretical capacity of about 260 mAh/g can be obtained.
The non-aqueous electrolyte produced by dissolving an electrolyte salt such as lithium tetrafluoroborate (LiBF4) or lithium hexafluorophosphate (LiPF6) in an organic solvent such as ethylene carbonate or diethyl carbonate is used.    [Patent Document 1] JP 2003-151549 A